Miling machine pulsator



Nov. l, 1932.y J. L.. HuLBl-:RT 1,885,110

' MILKING MACHINE PULSATOR 7 Filed July 9, 1931 ,irme/vf rs.

attested Nw. 1,".,1932- UNITED 'STATES PATENT ori-ics JOHN L. HULBERT, F POUGHXEEPSIE, NEW

YORK, ASSIGNOR TO THE DE LAVAL BEPABATOB COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW .JERSEY MILKING MACHINE P'CILSAJLOIB'.A

Application inea my 9, 1931. serial No. 549,696.

My improvement relates to automatic pneumatic pulsators for cow milking machines, and particularly to those machines wherein two pairs of teat cups are operated alternately. Machines of this generic type are disclosed in the Johanson Patent No.

' 1,363,878 and in the Hulbert Patent .No.

1,392,570. The object of the invention is to provide a pulsator wherein the action in the two pairs of teat cups will be exactly duplicated with respect to the timing of the peri- 4ods of pressure and suction.

One embodiment of my invention is herein described and illustrated apulsator with duplicate parts symmetrical about lthe center and in which, during operation, the time from the beginning of the movement in one direction to the beginning ofthe movement in the opposite direction is necessarily the 2 0 same as the time from the beginning of the movement in the last named' direction to the beginning o the movement in the first named direction; theconnections to the two pairs of teat cups being such as to necessarily produce balanced pulsations therein.

In the accompanying drawing of the said embodiment of my invention:

Fig. 1 is a longitudinal section: s

Fig. 2 is a cross section on the line 2--2 of and 3 is an enlargement of partof Fig. 1. 1, 2, 3, and l', 2', 3 are similar multidiameter pistons, which in operation are connected together and act as one double-ended piston symmetrical about the center of length. Each o these pistons comprises one large diameter portion 1 or 1', and two small diameter portions 2.and 3 or 2 and 3', connected by portions of still smaller diameter. Each plston carries, adjacent the large diameter portion 1 or 1' a rubber gasket ring 4 or 4. This double ended piston reciprocates in a cylinder having a central major bore 5, 5 of a size to fit the smallv diameter portions 2 and 3, 2' and 3', respectively, of the piston, shorter bores at opposite ends adapted to fit the large diameterpo-rtons 1, 1' respectively, and annular valve seats 6, 6 between the large bore and the small bores. Adjacent the cylinders io and communicating with their ends through passages in the heads 7, 7 are air chambers 8, 8'. Between the cylinders and air chambers and the end heads are soft rubber gaskets 9, 9 against which ma seat annular valves 17, 17 on the outer en s of the pistons 1,1.

Forts 10 and 10 communicate with a source of vacuum and ports 11 and 11 with the atmosphere. 12 and 12 are' restricted orts from the cylinder to the air chambers. l arallel and adjacent to the cylinder are two'pulsation passages 13 and 14. Port 15 connects cylinder 5 with passage 13 and port 15 connects cylinder 5 with passage 14. Restricted ports 16, 16' connect cylinders 1 and 1', close to the valve seats 6 and 6', with thepassages 13 valves 17, 17', when in contact with the rubber gaskets 9, 9', divide the head area into an inner area in communication with the air chamber 8, 8 and an outer annular area shut o" therefrom.

Assume that, because of the pressure in chamber 8 and the end of cylinder 1 having been relatively low and the pressure in chamber 8' and the end of cylinder 1' having been relativelyhigh, the piston has just completed its stroke to the left. Air entering atmos- 1 pheric port 11 -flows through port `15 and establishes atmospheric pressure in passage 13,

and also flows through the restricted port 12 and gradually raises the pressure in chamber 8 and the part 4of the left end of the cylinder inside the valve 17. At the same time air exhausts from passage 14 through port 15' and vacuum port 10' and. also exhausts from the right hand end of the -cylinder and chamber 8 through the restricted port 12. Atmospheric port 11 also admits air to the small annular space inside the seat 6', while air leaking past valve seat 6' (and which might otherwise cause premature movement) is exhausted from the annular space outside such valve seat through port 16 to passage 14.

When the pressure in chamber 8 and the left' end of the cylinder has raised and that in chamber 8 and the right end of the'cylinder has dropped until the difference is great enough, the piston begins to move toward the right. The initial movement takes valve seat 17' away from gasket 9, admitting pressure and 14. Y It will be observed that the l head 1. rllhe force due to these admissions with opposite ends of the of pressure to increased areas is enough to cause the piston to complete its stroke to the right almost instantaneously.

Air now enters chamber 8 through ports 11 and 12 and is exhausted from chamber 8 through ports 12 and 10 until the piston again moves toward the left.

The passages 13 and 14 are adapted to be connected one with one pair and the other with the other pair of a set of teat cups.

All ports, pistons, and passages provided at the left of the center are exactly duplicated at the right of the center, so lthat forces to cause movement in one direction are in turn exactly duplicated to cause movement in the other direction, the pauses at the two ends will be of equal duration, and the actions in the two pairs of teat cups will be equally timed.

Although, for purposes of manufacturevand assembly, the piston is made in two parts, such two parts are so connected together that in operation there is only one-moving element.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. In a milking machine pulsatorthe combination of a cyhnder, a reciprocable piston, ports and passages,` sources of high and low pressures, and two air chambers connected piston and adapted, in either end position of the piston, to be connected one with the source of highres- 40 I toward the other end sure and the other with the source o low pressure and eect the shift of the piston position of the piston, said piston, cylinder, ports and passages being symmetricalabout the center of length of the cylinder and piston to effect equal dwells' of the piston at opposite end posi-v tions.

2.- In a milking machine pulsator, a cylinder and piston, two egual chambers connected with opposite en s of the piston, two pneumatic pulsation conduits extending longitudinally of the cylinder 'and lston, sources of high and low pressures and) ports and passages adapted, in one end positions of the iston, to connect one conduit and one air c amber with the source of high pressure and the other conduit and the other air chamber with the source of low pressure, Iand adapted, in the other 'end position of the piston, to reverse said connections, said cylinder, piston, ports and passages metrical about the center of the cylinder.

3. In a milking machine pulsator, a cylinder and piston, two elual chambers connected with opposite en s of the piston, two pneumatic pu sation conduits extending lonbeing symgitudinally of the cylinder Vand piston, sources of high and low pressures and ports and passages adapted, ,in one end positions ber with the source of low pressure, and

adapted, in the other end position of the piston, to reverse said connections, said cyllnder, piston, ports and passages being symmetrical about the center of the cylinder, said air chambers being of equal capacity and positioned alongside the two symmetrical halves of the cvlinder.

4.-. In a milking machine pulsator, the combination of a cylinder, a reciproc'able piston, ports and passages, sources-of high and 4low pressures, and two air chambers connected with opposite ends of the piston and adapted, in either end position of the piston, to be connected one with the source `of high pressure and the other with the source of low pressure and eifect the shift of the piston toward the other end position of the piston, said piston, cylinder, ports and passages being symmetrical about the center of length of the' cylinder and piston to effect equal dwells of the piston at opposite end positions and means, operable in the initial movement of said piston away from an extreme end position, to increase the forces to complete s'uchmovement.

5. In a milking machine pulsator, the combination of a cyllnder, a reciprocable piston, ports and passages, sources of high land low pressures, and two 1air chambers connected with opposite ends of the piston and adapted, in either end position of the.piston,`to be connected one with the source of high pressure and the other with the source of low pressure and effect the shift of the piston toward the other end position of the piston, said piston, cylinder, ports andpassages being symmetrical about the center of length of the cylinder and piston to eiect equa] Adwells of the piston lat opposite end positions,

said piston having pressure surfaces adapted, in the initial movement of the piston, to be rendered operative to substantially increase the difference in pressures tending to move the piston inthe direction of initial movement, thereby eiecting a rapid completion of the pistons movement.

6. In a milking machine ulsator a cylin- I der,l a piston reciprocable t erein by pneumatic pressures, said cylinder and piston being each symmetrical about its own center of length, means to divide'the area subjected to pressure in thedirection of future movement into a plurality of parts under the influence of different pressures, and means whereby initial movement of the piston opens communication from a higher pressure to a lowerv pressure, thus greatly increasing the moving force.

' movement.

7. In a, milkngmachine pulsator, a single movable element symmetrical about its center of length, means to bring said element under the influence of opposin pneumatic pressures the resultant of w ich is initially opposedv to movement, said pres? sures being relatively variable so as to cause the resultant pressure to liltimatel cause movement, means for effecting sai variation in pressure, and meansl to remove leaking pressure Huid tending to cause premature ln testimony of which invention, I have hereunto set m hand, at Poughkeepsie, New

York, on this rst dalof J u1 J O L. BERT. 

